A fuse rejection kit is a critical safety accessory designed for use with safety switches. Its primary function is to ensure that only Class J fuses—which offer superior interrupting ratings and enhanced protection—can be installed. By physically modifying the fuse holder, the kit prevents the insertion of incompatible fuse types, thereby maintaining the integrity, performance, and safety compliance of the electrical system. When properly installed, the Class R Fuse Kit rejects all but Class J fuses. Used for 600A Series E3 General Duty Safety switches.